Is serial robber on the loose?

Police believe the same man tried to rob three San Antonio stores last night, WOAI-TV says.

Driving a green Chevrolet Blazer, he first robbed a Valero gas station on Potranco Road about 10 p.m., getting away with about $30, police said. He then tried to rob a Wal-Mart off West Military Drive, police said, but left empty-handed.

Less than an hour later, he stole $60 at a Valero gas station on Callaghan Road, police said.